In some cases it is desirable to shunt the magnetic field generated by a coil in an electromagnetic solenoid. Known electromagnetic solenoids achieve this by providing a radial groove in the outside surface of a pole piece adjacent to a flux sleeve. When the coil is energized, the magnetic field in the area of the radial groove will saturate and act as an air gap.
Current electromagnetic solenoids provide the radial groove on a hollow cylindrical end portion of the pole piece. As the armature is displaced in the flux sleeve towards the pole piece, it is guided to fit within the hollow interior of the cylindrical end portion. However, this configuration requires precise alignment of the flux sleeve with the pole piece to prevent contact between the armature and the interior of the pole piece. Contact is known to increase friction, and possibly preventing proper function of the solenoid. The precise alignment required to prevent contact slows production and may increase reject rate if the alignment is not properly maintained.
Accordingly, a need exists for an electromagnetic solenoid that less sensitive to misalignment between the flux sleeve and the pole piece.